Studies will be carried out in 4 groups of diabetic dogs with phenformin-induced lactic acidosis. In these animals, arterial lactate equals 9.0 mmol/L, bicarbonate equals 10 mEq/L and arterial pH equals 7.08. The animals will be treated with either (a) NaHCO3; (b) NaCl, (c) dichloroacetate, or (d) no treatment. Each animal in the aforementioned groups will receive an infusion of 1 ml/min, and in each case, the fluid infused will contain Na ion at a concentration of 1 mEq/ml. Thus, volume expansion and amount of Na ion infused will be the same in each group (except group (d), which will receive no therapy). Animals will be treated for either 4 hr, or until they expire. In each animal, serial measurements will be made of (1) arterial lactate, pyruvate, pHi, pCO2, and bicarbonate; (2) intracellular pH of liver and skeletal muscle; (3) cardiac output; (4) splanchnic blood flow; (5) splanchnic lactate production; and (6) ultimate mortality. The above studies will enable us to determine the efficacy of therapy in experimental lactic acidosis by evaluating well-defined guides to the success of each treatment.